Problem: What is the midline equation of $y=\sin(3x+5)$ ? $y=$
Midline in sinusoids of the form $y=a\sin(bx+c)+d$ Graphically, the midline of a sinusoidal function is the horizontal line that passes exactly in the middle of its extreme values. The midline equation of a sinusoid of the form $y={a}\sin(bx + c) + {d}$ is equal to $y={d}$. [How can we justify this given our graphical understanding of midline?] Finding the midline The midline equation of $y=\sin(3x+5)+{0}$ is $y={0}$.